WAVE ENTRAINMENT OF SAND FROM A RIPPLED BED

Proceedings of the International Conference on Coastal Engineering

Christopher E. Vincent¹  Malcolm O. Green² 

[1] School of Environmental Sciences, University of East Anglia;Bullard Laboratories, Department of Earth Sciences, University of Cambridge

关键词: rippled bed;    sediment entrainment;   

DOI  :  10.9753/icce.v22.%p

学科分类：建筑学

来源: Coastal Engineering Research Council

【 摘 要 】

Wave-orbital velocities at 20 cm above the bed and continuous vertical profiles of near-bed suspended-sediment concentration were measured seaward of the surfzone over a rippled bed. Sand was intermittently entrained from the bed and ejected upwards in discrete clouds. The typical sequence of events in the entrainment cycle, with sand being rolled up in a thin near-bed layer and ejected into the flow on alternating wave strokes, is attributed to the action of vortices shed from the bed ripples by the reversing flow. The orderly cycle of events causes a time-domain correlation between the wave fluctuations of velocity and concentration, and the resulting sediment flux is comparable in size, and at some elevations directed opposite to, the mean sediment flux.

【 授权许可】

Unknown